


Breaking the Oath

by Anonymous



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Age Difference, Anal Fingering, Anal Sex, Blow Jobs, Daddy Kink, Dead Dove: Do Not Eat, Finger Sucking, Incest, M/M, Multi, Parent/Child Incest, Praise Kink, Prostate Milking, Threesome - M/M/M, for real though
Language: English
Status: Completed
Published: 2020-07-09
Updated: 2020-07-09
Packaged: 2021-03-05 02:20:46
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 3,541
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25156888
Author URL: https://archiveofourown.org/
Summary: “Please.” Glenn’s voice is desperate and shrill and the impending source of Rodrigue’s nightmares. “Majesty, give me your seed.”
Relationships: Glenn Fraldarius/Rodrigue Achille Fraldarius, Lambert Egitte Blaiddyd/Glenn Fraldarius, Lambert Egitte Blaiddyd/Rodrigue Achille Fraldarius
Comments: 12
Kudos: 41
Collections: Anonymous





	Breaking the Oath

The first time Rodrigue finds them, he manages to look away.

It’s the first instinct that fails him. He can’t block out everything. He can certainly hear. Hear the way the sheets are disturbed as they’re pushed around—the ends gathered together, harshly fisted. Hear something shoved aggressively into Glenn’s mouth until he gags. Hear the way the royal headboard creaks in tandem with the deep sighs and high, needy whines. Hear the way the King of Faerghus’s balls slap against his ass. Rodrigue knows without a shadow of a doubt that Lambert is taking his eldest son from behind.

Fifteen. He’s fifteen. He’s practically a boy.

How they ended up like this...Rodrigue couldn’t imagine. He sent Glenn here in good faith. He sent him here to serve the crown prince. For centuries now, Fraldarius has followed the tradition. How dare Lambert treat his son—Dimitri’s future shield—as he would a harlot? How dare Lambert do this to him—to all of them? How dare he destroy something so very sacred?

How dare he, himself, return to his office to fill his fist with seed at the thought of what he might have seen if he dared to open his eyes?

Goddess save him. Goddess save them all.

He’s quiet at dinner—contemplative. Rodrigue studies Lambert, scrutinizes the man he was certain he knew, the man he trusted more than anyone on earth, the man he never would have expected to risk loyalty and honor in such an immoral way—there’s nothing on the surface that indicates he’s changed.

Glenn is as somber as ever—impassive. Rodrigue has never been able to read him. He’s nothing like Felix—hotheaded and deeply sensitive and beginning to adopt a sharp tongue. Glenn is stoic. He is careful and he is diligent. He is the perfect image of a properly raised noble and, up until this afternoon, Rodrigue had thought him chaste. Glenn has never shown interest in any of the potential nobles hoping to marry into their bloodline. He’d suspected the rejection to stem from Glenn’s strict dedication to knighthood—and his youth. Rodrigue never suspected it was because his son was interested in the King.

Prince Dimitri sits at his side, tugging on his father’s sleeve. Lambert smiles warmly, leans down to place a kiss on his forehead—two more on each cheek. Dimitri giggles, and returns to his meal, a small flush setting by the spots where his father brushed his lips. He is Felix’s age, and Rodrigue’s heart slams into his throat. There’s no way Lambert would dare lay with his own son, is there? No—he is far too ahead of himself to consider such an accusation. He must control his worries before they devolve into baseless accusations. He could not make any further judgements until he’s gathered enough evidence.

He didn’t see anything, after all. Rodrigue could be wrong.

Tomorrow, he returns to the scene of what he prays with all of the faith he has within himself is not a crime.

This time, Rodrigue opens his eyes.

They are clothed, initially, and Rodrigue is grateful. The scene is still unmistakable. It is grievous. It is _sin_. Lambert has Glenn pinned beneath him—his Glenn, his _son_ —fingers shoved into his mouth, thrusting, spit spurting out the sides, soaking the bed sheets. The noises Glenn gives in return make Rodrigue want to screech and tear his eardrums apart. It is, undeniably, the same sounds he heard coming from the King’s chamber yesterday—and there is more. Much more.

Glenn ruts against the bed, humps at the little wet spots there in search of relief. Lambert holds him close, so intimately breathes down the back of his neck, kissing under the collar of his threadbare underclothes. It is beginning to stick to the teen’s skin—sheen and sheer from sweat. Lambert notices, and pulls his fingers free with a sickening pop to remove it. Glenn raises his arms over his head, drools sloppily. The fresh spit is absorbed into a damp circle already nearby, widening it. How many times has His Majesty shoved his fingers down Glenn’s throat that it would coalesce like this?

“Good. Good boy. Always so very eager.”

Lambert strokes his jaw unhinged, holds it there. Firm. Open and wanting. He simply stares into it for some time—beams, in fact, with the sort of pride one would show to an award winning racehorse. It sickens Rodrigue— _oh_ , how it sickens him!—that Lambert would view his son like that. See him as a simple hole. Measure his value by the favors he can offer his body.

“Tell me, how shall I take you today?”

A wandering thumb finds its way into Glenn’s mouth, poking and prodding. The only answer it elicits is a moan. Glenn seems to enjoy this activity even more than the previous one, letting his head fall on his shoulder—sighing—heavy eyes that Rodrigue had never witnessed outside the premise of encroaching sleep.

“You’re still slick from earlier, I’m sure.” Lambert continues to speak, revealing more than what Rodrigue came here for. Glenn licks at Lambert’s fingers earnestly, fully immersed in the project, but manages to nod as he runs his tongue in-between. “So warm and wet and ready for me.”

Glenn hums. He closes his eyes and arches back, more graceful than Rodrigue has ever seen him in combat. Lambert draws his cock out of his small clothes and rubs it against Glenn’s entrance, leaving sticky beads of precum, teasing what is to come.

“What do we say, Glenn? What do we say when we are propositioned by the King?”

Rodrigue’s breath halts alongside his son. Why is he listening? Why has he not stepped forward yet to say something? A familiar warmth begins to flood his body. A tingle that begins in his head and will not relent until far after it has spread to his feet. No. It cannot be.

“We say please.” Glenn responds immediately. Mechanically, as if he is repeating a line fed to him until it becomes a mantra.

“That’s right.” Lambert kisses him gently as he removes the rest of their clothes.“That’s my good boy.”

Rodrigue’s fingers tremble in midair. He is unaware just when they started reaching, but they fall short—so short—of their target. Glenn is impossibly far from him—wrenched—his innocence, long behind. The King and the Knight are too close. Their exchange is too practiced. He has failed— _failed_ —to think he need not prepare to prevent something like this. He has failed as a father, a person, a friend.

He is beside himself with fear and disgust and some other nameless disquietude, about to brave the interruption anyway when, once more, he breaks.

“ _Please_.” Glenn’s voice is desperate and shrill and the impending source of Rodrigue’s nightmares. “Majesty, give me your seed.”

Whipping his overheated face back to display his urgency, the heir of Fraldarius begs. Rodrigue has never heard him plead in his entire life—he’s never once heard him complain. Glenn has endured some of the harshest training Faerghus has to offer and succeeded his own father as a Knight at a much earlier age with nary a tear, but now he cries for Lambert’s cock without shame. Roots around for it like a newborn babe searching for its first meal.

Rodrigue should not watch, but he is glued to the spot. Some invisible string of fate ties him there, pulls his eyes until they are straining to slip out of their sockets. Pulls his cock from his pants, half-hard and throbbing.

“Oh how good you are to me, Glenn.” Lambert nuzzles him, slips two fingers into his waiting heat. Glenn groans and fucks back onto them. Grabs his own cock and strokes himself—harsh and fast—like he’ll perish if he doesn’t come within the following second. He is powerful, a picture of beauty, mouth agape, eyes rolling back into his head, and in this moment Rodrigue cannot find he blames Lambert one bit. There is no way Rodrigue could have known Glenn would look like this. If he had, and he were in the position to be tempted, there’s no telling what he might do.

There may be a bit of a monster in him yet.

“You take my fingers so well, Glenn, just like my cock, so perfect my boy.” Lambert praises him, scissors, matches his pace. Obscenely loud and deliberate, he pounds into Glenn—takes his own pleasure from it, while Rodrigue submits to the reality that he is also taking his. His cock swells in his palm, seeking relief. His head swarms with hot air, like a bursting tea kettle. His heart burns with jealousy. Which of the two triggered it, he could not say. He’s forgotten his initial agenda. This situation had evolved into something else entirely.

“Don’t.” Glenn grits out, and Rodrigue pauses, pulse quickening. Had they discovered him? “Don’t...don’t stop.” He continues, already a sticky panting mess. He presses even closer into Lambert, arching up, cock hard and leaking, high against his stomach as he slows his strokes.

“Please.” He’s breathless, trying to become one with Lambert’s hulking form. He’s begging again. Begging over clothed dry humping and a few fingers? How much had Lambert trained him to bring him to this point already? “Fuck me—quickly—before I come.”

Rodrigue’s cock leaps up into the flames of his gut. He’s never wanted to see anything more in his life.

“Of course.” Lambert slips another finger in—rocks Glenn through his whimpers, lovingly. Three of them now, stretching his son in ways Rodrigue never knew he needed to be stretched. Three of them, twisting and curling to press against his prostate, making his cock leak copiously, making an absolute mess of him.

“ _Ah_!” Glenn claps a hand over his mouth at the outburst. Tears sting at his eyes—so shiny, so tangible that even from his peephole, Rodrigue can practically taste them. Glenn’s cock begins to spill clear fluid that he gathers in his hand, uses to jack himself off even faster. Rodrigue matches his vigor, absolutely spellbound.

“ _Daddy_.” Glenn gasps. “Rodrigue!”

Lambert laughs, with a sense of familiarity that strikes Rodrigue clean through his core. Glenn is crying openly now, iterations of his father’s title and his name, and Rodrigue can scarcely believe his ears. He did not hear this yesterday. He did not—he could not have—how could he forget something so profane?

“I am not your father, my boy.” Lambert raises his head, gleaming cyan irises waving directly over to the corner where Rodrigue stands behind the curtain, shell-shocked—in retrospect, a poor hiding space. “Ask him yourself. He’s right over there.”

Glenn jerks, shudders, continues to pour the thin, milky fluid. His loose navy braid swings—a nuisance, or a tool, perhaps. Lambert grabs it, rolls it around his hand and halfway up his wrist, lines his cock up with Glenn’s pink, puckered hole.

“Shall I ask him to join us?”

Rodrigue grips the thick curtain as if it were the only thing bridging him to gravity. His cock bobs in the cool air—angry at the sudden abandonment. His knees threaten to fold. Glenn’s hazy eyes carry enough vision to vaporize him on the spot. How could he do this? What kind of father is he to allow this to go on? What kind of father is he, to hide here, like it is _a game_ , finding some sick pleasure out of it?

What kind of father is he, if he accepts?

“Come out, my friend.” Lambert calls to him. Years of training and close companionship have made it automatic for Rodrigue to follow his command. Glenn smirks as he steps forward and Lambert—staring directly at his father’s reaction—begins to sink into him. Rodrigue’s brain is so busy—too busy—drinking in all the minute details he could not take in from a distance. His son is beautiful, all marked up and on the verge of climax. He’d always known, but refused to see it, as Lambert did.

“Hey, Dad.” Glenn says, suddenly regaining control of the situation, ass up, side of his face pressing into the pool of his fluids on the bed, coy smile as he lets Lambert begin to move him as he pleases. “you want in?”

 _Such confidence_. Had they known then—that he was watching? Had they orchestrated this?

Rodrigue is hit with several different urges, some which are difficult to categorize, others which are impossible to comprehend. Lambert fucks Glenn deep and hard—merciless. He smacks loudly against Glenn’s ass, does not think to stop for even a moment to give either of them the reprieve to process this. Glenn’s cock is dribbling again—how is there possibly anything left—and Goddess, Rodrigue is parched just looking at it. How strong willed must he continue to be?

May Sothis avert her eyes for just this moment.

“Rodrigue.” Lambert directs him, voice dripping with the same honeyed quality he used earlier when he was talking to Glenn. “Glenn has served me well. I think you should reward him.”

Reward him. Meaning he should take Lambert’s place. Meaning he should fuck his own son. Meaning this has spiraled way, way beyond what was acceptable behavior. He comes closer still, reaching out to run a finger down the arch of Glenn’s spine, watching as Lambert’s powerful thrusts push it forward. Rodrigue has lost sight of anything not immediately laid before his eyes.

He wants this.

“Lambert.” He is hoarse, but steady. Resolute. “Tell me. How does he feel?”

Glenn wiggles his ass as he shoves it back—grinds and gapes and wails at his father. Rodrigue’s pride. His joy. Usually so sensible. Glenn has never been one to seek attention, but here and now he laps it up like a dog. It’s disgraceful, and vulgar, and if Rodrigue were to spend the rest of his life watching his son bounce on a cock like this, he still would not have enough of it.

“Like a saint.” Lambert licks his lips. “Truly and utterly. Goddess sent.”

That’s all he needs to hear. That, and that Glenn would have him.

“ _Daddy_ ,” Glenn laments again, fresh, overstimulated tears gathering in the corner of his eyes as he’s spanked and impaled on His Majesty’s cock. He can’t seem to say or see anything else—it’s like he’s gazing through the clouds, but Rodrigue is here. _He is here_.

He’ll be sure to provide Glenn with whatever he needs. It’s what a father does.

“Yes, Glenn?” Rodrigue runs a hand under his jaw—soothes him—wipes the tears as they fall. “I’m here.” Lambert rolls his hips at a new, startling speed, pushing Glenn up high enough that Rodrigue can snap him out of his stupor. “What do you need?”

“Fuck me—“ he cuts off, breathless. “M..my mouth... _please_.”

With that request, the rest of Glenn’s energy fades; he adopts a dreamy, distant expression. Rodrigue takes a minute to compose himself. He wants to memorize this—to never forget the first time Glenn asks for him. His oldest. His firstborn. Demands, then begs for his cock. Does so like a wanton whore. Immediately stretches his mouth as far as he can manage, then retreats into a headspace where nothing but his cock can reach him.

“ _Rodrigue_.”

Oh. It has been long— _too long_ —since Rodrigue heard his name spoken in such reverence. Lambert. The only voice that could stand out from this flurry of affairs. His King. The only one he would ever bow to. Lay down his life for. How he aches to hear Lambert call upon him once more.

Rodrigue is torn into shreds—fragments, jagged and treacherous. The darkness in his heart that he cannot blot out belongs to the war between the oath to his country and the fulfillment of his first love. The clashing is never-ceasing and volatile. Today, love wins out.

“What do we say…” Lambert’s lips touch his briefly and Rodrigue could sing a book of hymns about it in the many coming days.

“...when we are propositioned by the King?”

He was a fool to think that it was merely Glenn who had fallen into this perverse indoctrinate. Rodrigue studies the blank look on his son’s face—blissful, doe-eyed, body moving like it was born to be filled with the seed of high nobility. Perhaps it was. Rodrigue knows what it feels like now, to jump from the top of a tower into the depths of a river with no fear. To trust implicitly that the ones you hold dearest to your heart will be there to catch you—pull you to shore.

There is no more hesitation between the three of them. Rodrigue’s hand comes up to join with Lambert’s—tangle them together in his hair.

“Please.”

The hand tightens momentarily, then moves—comforting him. “Good.” Lambert kisses him again. Properly this time. Rodrigue tilts his head to the side and leans into it, fingers rubbing the side of Lambert’s jaw down into his neck. “Go fuck your son.” He orders Rodrigue as soon as they part, forehead against forehead. “I’ll show you how to use him.”

Lambert whispers encouragement into his ear, urging Glenn on with another round of slaps. _Goddess_ , but Glenn has changed. He used to be so small. Now he is almost Rodrigue’s height, his chest and shoulders thickening. The baby fat Miklan used to tease him about is hardly perceptible, clinging only in sparse amounts on his otherwise toned abdomen. He is a mixture of Felix’s future, and Rodrigue’s past. The proof is here, where he’s followed directly in his father's footsteps—ended up cock drunk and heartbroken for His Majesty, the King. The proof is here, where just as Rodrigue once begged for his own father to besoil him, Glenn’s lips part to wrap around his weeping cockhead. Rodrigue’s ears are pounding with the rush of his own heartbeat, chest tight with adrenaline.

Glenn grabs him by the hips, impatient. Rodrigue jerks forward with a surprised grunt. In one fluid motion, his son has swallowed him. It should send him to hell, the way Glenn stares him down like a starving wolf, the way Rodrigue struggles not to take a hold of his skull and subdue him. Instead, he hisses and snaps the tie of Glenn’s braid, working the tresses free and remaining as still as he can. Glenn takes him, takes the both of them, deep as they can go—in a silent, sustained scream.

“What a sight you two make.” Lambert speaks as if they are kneeling at a cathedral instead of a war zone. “So intimate and genuine. Father and son.”

 _Lambert is right_. Rodrigue cannot help but to think so, watching Glenn slobber so pretty on his cock. _He takes me like he was meant to do it._ He has never seen Glenn look so alive—so at peace with himself. How can this be wrong? His boy. Not yet a man, but already so attentive and sacrificial. A rightful heir. One who serves. Glenn. _His_ Glenn.

He’s not going to last. It’s a miracle he’s made it this far. A miracle and a curse, that he is here. Rodrigue simply stands, watching the love of his life fuck his son into another dimension, balls hot and tight and heavy with seed. Glenn senses it, pulls back to use his hands, one cradling Rodrigue’s balls and the other sliding up his shaft while he moves the foreskin around with his tongue and sucks vigorously on Rodrigue’s cockhead. It’s impressive to Rodrigue that he can retain the consciousness to continue. The fury with which Lambert pounds his son into the mattress is enough to make anyone gag. Rodrigue has been in Glenn's position before—many times before—the power that lies in the crest of Blaiddyd is not a thing to be trifled with.

“It’s okay.” He tries to hold Glenn’s head still as best as he can, spurting ropes of come into his mouth, shuddering as Glenn drains him, as he hears Lambert curse and slow his unrelenting pace with each stroke—until Glenn breaks away with a gasp and it is only him left to spill onto the thoroughly soiled sheets. “It’s okay.” The croon comes again—again, as many times as he needs to say it. As many times as he needs to hear it to believe. Not Glenn, not Lambert, but himself—Rodrigue.

 _It’s okay._ He tells himself, wiping his semen off of Glenn’s lips before he can collect the memento. _Our love is not a lie. Not a dream_. Rodrigue reminisces, he accepts. He’ll do better with Glenn. He will. He can. Leaning over to kiss his eldest, Rodrigue tastes the springtime, hindsight and wisdom, together. Glenn is, in so many ways, a mirror of their ancestors, but in no way before them, Rodrigue is here to show him that there is hope.

He swore an oath after all, and he broke it—linking one chain to another. For King and for country. For love and for doctrine. For Lambert—and for Glenn.


End file.
